Nearly every desktop computer and server in use today contains one or more disk drives. These disk drives function to store digital information on a magnetic medium. Conventional disk drives typically include a base plate and a cover that is detachably connected to the base plate to define a housing for various disk drive components. One or more data storage disks are generally mounted on a spindle which is interconnected with the base plate and/or cover so as to allow the data storage disk(s) to rotate relative to both the base plate and cover via a spindle motor. An actuator arm assembly (such as a single actuator arm, a plurality of actuator arms, or an E-block having a plurality of actuator arm tips), is interconnected with the base plate and/or cover by an appropriate bearing or bearing assembly so as to enable the actuator arm assembly to pivot relative to one or more of the base plate, cover, and the data storage disk(s) in a controlled manner.
A suspension or load beam may be provided for each data storage surface of each data storage disk. Typically each disk has two of such surfaces. All suspensions are appropriately attached to and extend away from the actuator arm assembly in the general direction of the data storage disk(s). A transducer, such as a read/write head, is disposed on the free end of each suspension for purposes of measuring/writing signals with the corresponding data storage disk. The position of the actuator arm assembly, and thereby each transducer, is controlled by a voice coil motor or the like which pivots the actuator arm assembly to position the transducer(s) at the desired radial position of the data storage disk.
Each data storage disk has a plurality of concentrically disposed tracks which are available for data storage. These tracks are formed on the data storage disk(s) after they have been enclosed in the space between the cover and base plate. One way in which this is accomplished is by including a push-pin hole on the base plate of the disk drive. Formation of the tracks on the data storage disk(s) of the disk drive entails directing a push-pin through this push-pin hole in the disk drive base plate and into engagement with the actuator arm assembly. This push-pin is part of a servo writer which moves the push-pin in a controlled manner to a position where the actuator arm assembly is disposed for writing a track on the disk(s) at a specific radial location on the disk(s) via the relevant read/write head.
It is important to precisely control the position of the actuator arm assembly while the servo information fields are written to the disk surfaces. However, system resonances can arise, for example, from vibrations generated by the operation of the spindle motor during rotation of the data storage disk(s). Of particular interest are resonances which occur locally at the push-pin and actuator arm assembly, as such resonances are most likely to affect the position of a read/write element on the actuator arm assembly interfacing the disk(s) where servo information fields are read and/or written. Steps have been taken to reduce these resonances, including efforts to stiffen the push-pin and the associated push-pin assembly, as well as installing a soft, energy-absorbing material between the push-pin and the actuator arm assembly. However, to date such efforts have not been completely successful in eliminating the effects of resonances during the writing of the servo information without adding additional complications to the process. For instance, such energy-absorbing material greatly increases the incidence of stiction which can potentially cause unwanted track spacing and/or jumping. As track densities continue to increase, such track spacing errors in the writing and/or reading of the servo information will increasingly prove problematic during disk drive operations.
Thus, a need exists for an improved approach to reducing the resonances from a disk drive servo track writer, via the push-pin, in order to reduce or eliminate the affects of resonances which influence the position of the actuator arm assembly and hence, the location of each read/write head with respect to the desired location. At the same time, a need exists to enhance the structural characteristics and/or dynamics of the push-pin with respect to its interface with the actuator arm assembly to prevent the occurrence of stiction.